Heat treating apparatus



Allg- 12, 1958 v. H. FERGUSON A 2,847,203-

HEAT'TREATING APPARATUS 3 Sheets-Sheet 1 O MN INVENTOR. VfR/veu A.Ffeauso/ BY om Aug. 12, 1958 v. H. FERGUSON HEAT TREATING APPARATUS 3Sheets-Sheet 2 Filed April 30, 1956 mu ...mww

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Aug. l2, v1958 V. H. FERGUSON HEAT TREATING APPARATUS 'Filed April 3o,1956 5 Sheets-Sheet 3 INVENTOR. L/-,efvan Enea/:wl BY wl lm/w m f HEATTREA'IING APPARATUS Vernon H. Ferguson, Pittsburgh, Pa.

Application April 30, 1956, Serial No. 581,727

3 Claims. (Cl. 2664) This invention relates to heat treating apparatusfor metal articles, and more particularly to apparatus for performing acomplete heat treating operation automatically.

It is among the objects of this invention to provide such apparatuswhich can be Shipped and installed as a complete compact unit ready tooperate when connected to utilities, which can easily be moved from onelocation to another, which requires a minimum of floor area and verticalspace, which is of substantially uniform width from end to end, whichcan be loaded and unloaded from the same end, and which permits aplurality of groups of different types of articles to be heat treatedsimultaneously without mixing.

In accordance with this invention, a lower tempering furnace is loadedat its rear end and discharges heated articles fromits front end. Aconveyor extends forward through the furnace to convey the articlestherethrough. Mounted on top of the lower furnace is a hardeningfurnace, which is loaded at its front end and has a discharge opening atits rear end behind the lower furnace. A conveyor extends rearwardlythrough the upper furnace. Also mounted on the lower furnace in front ofthe upper furnace is apparatus for automatically feeding the articles tobe heat treated to washing, rinsing and drying means before they enterthe upper furnace. Disposed behind the lower furnace, below thedischarge end of the upper furnace, is a quenching tank in position toreceive heated articles discharged from the upper furnace. A conveyor inthis tank carries the articles back through it and out of its rear end,where they are delivered to the rear ends of a pair of conveyorsextending forward along the opposite sides of the tank. Each of theselast-mentioned conveyors extends through a washing tank Where thequenched articles are cleaned. Between the quenchingtank and the lowerfurnace, there are transverse conveyors which connect the front ends ofthe cleaning tank conveyors with the lower `furnace conveyor so that thearticles will ultimately be discharged from the front end of the lowerfurnace. It will be seen that after the 1 articles are delivered to theloading mechanism, they are automatically carried through this entireheat treating operation and discharged at the front end of theapparatus.

The preferred embodiment of the invention is illustrated in theaccompanying drawings, in which- Fig. l is a longitudinal verticalsection through the apparatus;

Fig. 2 is a horizontal section taken on the line II-II of Fig. 1;

Figs. 3 and 4 are transverse sections taken on the lines wlll- Ill andIV--IV, respectively, of. Fig. l;

847,23 Patented Aug. l2, 1958 Fig. 5 is an enlarged transverse sectiontaken on the line V-V of Fig. l; and

Fig. 6 is an enlarged fragmentary horizontal section taken on the lineVI-VI of Fig. 1.

Referring to the drawings, a tunnel type tempering furnace 1 is mountedin the lower part of a structural steel framework 2 that is rectangularin plan View, as shown in Fig. 2. This furnace has an exit 3 at thefront end of the apparatus and a loading entrance 4 at the rear end. Aconveyor of any suitable form is provided for transporting articlesforward through the furnace. For example, extending through the furnaceand its entrance and exit openings, there may be a pair of parallelhorizontal channels 6, each of which supports an endless conveyor belt 7of metal mesh. The belts are moved forward through the furnace by anysuitable driving mechanism 8 supported in the front part of framework 1.The lower lengths of the belts travel back beneath the furnace and uparound takeup drum 9 mounted in the framework a short distance behindthe furnace. The inside of the furnace is heated in any convenientmanner, such as by electric heaters ll. An electric blower l2 inside thefront part of the furnace near its roof, draws the furnace atmosphere upto the roof and then forces it back through a duct i3 to the back of thefurnace for recirculation.

Mounted above the front portion of the tempering furnace, as shown inFig. l is a feeder for feeding metal articles into thisapparatus. Whentwo conveyor belts are used in the furnace, the feeder includes twoparallel hoppers l5 provided with forwardly and downwardly inclinedbottoms f6 and vertically adjustable articlecontrol gates i7. Near thelower end of each hopper bottom, there is a paddle wheel 18 that helpsto discharge the articles, which have been deposited in the hopper, ontoa forwardly moving metering belt 19. r[he belt dumps the articles ontoshort slides 21 that feed them back to the front ends of a pair ofparallel conveyors 22, such as shuiiie trays, which extend rearwardlybelow the hoppers and project from their rear ends, These trays, whichare perforated, are reciprocated by suitable means 23 below them. As thearticles start back beneath the hopper, they are first washed by spraynozzles 24 and then rinsed by other nozzles 25, and then they passthrough a drying chamber 26 where heated air is `blown against them todry them.

The rear ends of shuffle trays 27. empty onto the front ends of anotherpair of conveyors, which may be shuffle trays 28 reciprocated bysuitable reciprocating mechanism 29 mounted on the central portion ofthe tempering furnace. These last conveyor trays extend back into atunnel type hardening furnace SiLthe front half of which is disposeddirectly above the rear portion of the tempering fumace and practicallyrest von it. The upper furnace extends a considerable distance behindthe lower furnace, and has an exit at its rear end preferably extendingdown through the bottom of the furnace. The trays 28 are moved atvarying rates of speed, depending on the genwalls of the furnace. Ifelectric heating, for example, is used, it would not be necessary toemploy muftles.

The lower ends of the two chutes empty into the front portion of aquenching tank 35 spaced behind the rear end of the lower furnace. Thetank extends behind the upper furnace and is kept nearly full ofquenching liquid. A hood 36 surrounds the lower end of each chute andextends down into the liquid. The hoods are considerably larger than thechutes. The reason for providing these hoods or enlargements for thelower ends ofthe chutes, is to greatly minimize splashing of the oil upthe chutes into the furnace when the articles fall into the quenchingtank. Such splashed oil forms carbon deposits and, by cooling onlyisolated areas of the hot articles, is likely to deform them. The largehoods also provide large areas for accumulation of the gases that areformed when the hot articles strike the oil. Between the time that agroup of thefarticles falls off the end of a shuflie tray and the timethat the next group is fed forward into the chute, the gases arewithdrawn from the hood through an opening 37 near its top, andtherefore do not rise into the furnace. These gases would be harmful ifallowed to rise up into the chutes, because they contain carbonparticles that form deposits. Such gases would also affect the work inthe furnace chamber, causing slightly irregular surface conditions onthe work pieces, which appear to cause additional distortion when thework is quenched, due to slightly different quenching rates.

When the articles heated in the upper furnace reach the rear ends of theconveyor therein, they fall through the chutes and hoods into the liquidin the quenching tank and land on a conveyor. This conveyor preferablyis composed of a pair of endless mesh belts 40 that pass around a drum41 journaled in the front part of the tank and also around a drivingdrum 42 mounted above the back wall of the tank. This upper drum isrotated by drive mechanism 43 mounted above 'the tank in a housing 44that separates the tank from the outside atmosphere. A length of eachbelt is maintained horizontal in the tank by means of small drum 4.5that engages the top of the lower portion of the belt, and by means ofsmall rollers 46 that engage the top of the belt at its opposite sides.

The quenched articles fall off the upper or rear end of the tankconveyor and onto chutes 48 that are inclined laterally toward theopposite sides of the apparatus. The lower ends of these chutes emptyonto the rear ends of shuffle type conveyors 49 that extend forwardalong the opposite sides of the quenching tank. These conveyors, whichhave perforated bottoms, are reciprocated by suitable mechanisms 50.Each conveyor is located in the upper part of a narrow cleaning tank S1that extends along one side of the quenching tank, and a spray pipe 52extends along the top of the conveyor. These pipes wash and rinse thequenched articles as they move forward along the shuie conveyors. Theconveyors extend forward beyond the tanks a short distance, and eachterminates above a short transverse conveyor in the form of a tray S3that is vibrated lengthwise by suitable means 54 beside the apparatus,as shown in Fig. 6. Each of these transverse conveyor trays extendsacross the rear end of one of the conveyor belts 7 in the lower furnace.The bottom of the tray is provided with a rectangular opening, but thisopening is generally partly closed by an adjustable plate 56 so that theremaining slot S7 therethrough is triangular and flares out from a pointbelow the adjacent cleaning tank conveyor toward the inner end of thetransverse conveyor. This general shape of slot assures substantiallyuniform feeding of the articles across the lower furnace belt. As thequenched articles travel forward through the lower furnace, they aretempered and finally are discharged from the front end of the furnace.

It will be seen that with this apparatus only one attendant is required,who can look after several of these units. He can stand at the front ofthe apparatus and watch the feeding of articles to the first washingunit and the delivery of the heat treated articles from the lowerfurnace. As everything is enclosed, a controlled atmosphere throughoutthe apparatus or at any desired location therein is possible. By placingthe feeding and first washing apparatus and the hardening furnace abovethe tempering furnace and the quenching tank, considerable floor spaceis saved and the apparatus is made very compact. Yet, its height is low,which makes it possible for all processes to be observed from oor levelby a single operator. It will be noted that the combined width of thequenching tank and the cleaning tanks beside it is no greater than thewidth of the rest of the apparatus, because the cleaning tank conveyorsextend forward below the upper furnace. Consequently, this apparatus canhave the same uniform width from front to back, thereby making it easyto fit into a plant, or onto railroad cars for shipment. The cleaningtank conveyors and the transverse conveyors to which they deliver haveno effect on the height of the apparatus. lt will be observed that thisapparatus performs six consecutive operations, all entirelyautomatically. They are automatic loading, prewashing and drying,hardening, oil quenching, washing and drying, and tempering.

According to the provisions of the patent statutes, l have explained theprinciple of my invention and have illustrated and described what I nowconsider to represent the best embodiments. However, l desire to have itunderstood that, within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically illustrated anddescribed.

I claim:

l. Heat treating apparatus for metal articles, comprising a lowerfurnace having a loading rear end and a discharge front end, a conveyorextending forward through the furnace, an upper furnace mounted on thelower furnace and having a loading front end and having a discharge rearend projecting behind the lower furnace, a conveyor extending rearwardlyin the upper furnace, a quenching tank disposed behind and atsubstantially the same level as the lower furnace and belo-w thedischarge end of the upper furnace in position to receive heatedarticles discharged from the upper furnace, a conveyor in the tankadapted to carry said articles back through the tank and out its rearend, a cleaning tank extending along each side of the quenching tank, aconveyor extending forward through each cleaning tank, conveyor meansconnecting the rear end of the quenching tank conveyor with the rearends of the cleaning tank conveyors, and transverse conveyors locatedbetween the quenching tank and lower furnace and connecting the frontends of the cleaning tank conveyors with the lower furnace conveyor atits loading end, whereby said articles will be discharged from the frontend of the lower furnace.

2. Heat treating apparatus according to claim l, in which the combinedwidth of the quenching and cleaning tanks is substantially the same asthe width of the upper furnace, and said cleaning tank conveyors extendbeneath the upper furnace.

3. Heat treating apparatus for metal articles, comprising a lowerfurnace having a loading rear end and a discharge front end, a conveyorextending forward through the furnace, an upper furnace mounted on thelower furnace and having a loading front end and having a discharge rearend projecting behind the lower furnace, a conveyor extending rearwardlyin the upper furnace, a quenching tank disposed behind and atsubstantially the same level as the lower furnace and below thedischarge end of the .upper furnace in position to receive heatedarticles discharged from the upper furnace, a ccnveyor in the tankadapted to carry said articles baci: through the tank and out its rearend, a cleaning tank extending along each side of the quenching tank, aconveyor extending forward through each cleaning tank,

tween the quenching tank and lower furnace in positions` to receivearticles near their outer ends from the front ends of said cleaning tankconveyors, and means for reciprocating the transverse conveyorstransversely of the cleaning tank conveyors, each of said transverseconveyors being provided in its bottom with a slot tapering from a pointnear the inner end of the conveyor to a point near its outer end, saidslot being located above the loading end of the lower furnace conveyorfor distributing said articles across the furnace conveyor.

References Cited in the tile of this patent UNITED STATES PATENTS McCannMay 1, 1928 McCann Jan. 1, 1929 Shanafelt et a1. May 24, 1932 Webb Mar.6, 1934 Langhammer etal Mar. 16, 1937 Darrah Dec. 3, 1940 Roth Sept. 2,1941 Loux Mar. 16, 1948 ISbell June 29, 1954

